Field of the Invention
The invention relates to a display system, and particularly relates to head-mounted display (HMD).
Description of Related Art
Near eye display (NED) and head-mounted display (HMD) are the most promising killer products of the next generation. Related applications of the NED technique are presently divided into an augmented reality (AR) technique and a virtual reality (VR) technique. Regarding the AR technique, relevant developers are currently working on how to provide the best image quality under the premise of light and slim.
In an optical architecture of using the HMD to implement the AR, after an image beam used for displaying is sent by a projection device, the image beam enters an eye of a user through waveguide. An image coming from a light valve and an external environmental beam enters the eye of the user through the waveguide, so as to achieve the effect of AR. In HMD products, since a distance between the waveguide and an optical engine mechanism is too close, the environmental beam is blocked from entering the eye of the user, which spoils a sense of immersion, and the effectiveness of AR is greatly reduced.
Regarding a demand on the HMD, the HMD is expected to be closer to a design of general myopia glasses or sunglasses, so that how to move the huge optical engine to the outside of a user's visual area to avoid blocking a line of sight of the user is one of the most important issues currently. Moreover, a magnitude of a field of view (FOV) provided by the HMD and a volume of the HMD are also important factors that influence a user experience.
The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art.